Total ionizing dose (TID) effects induced by 1 MeV electron and 5 MeV proton on the dc electrical characteristics of 200 GHz silicon germanium heterojunction bipolar transistors (SiGe HBTs) were investigated. These results were compared with ⁶⁰Co gamma irradiation results to understand the linear energy transfer (LET) effects on the electrical characteristics of SiGe HBTs. The different electrical parameters like forward and inverse mode Gummel characteristics, excess base current (ΔI_B), current gain (h_FE) and output characteristics (I_C-V_CE) were systematically studied before and after irradiation. The electrical characteristics of irradiated SiGe HBTs degrade with increase in total dose. The more degradation in device parameters was observed in case of 5 MeV proton irradiated HBTs when compared to other radiations. The irradiated devices were also subjected to isochronal annealing to analyze the recovery of electrical parameters.